In order to increase the energy density and power of lithium-ion batteries, metallic materials that can form alloys with lithium, such as silicon, germanium, tin, and zinc, and oxides of these metals have been studied as negative electrode active materials, instead of carbonaceous materials, such as graphite.
It is known that negative electrode active materials composed of metallic materials that can form alloys with lithium and oxides of these metals expand or contract during charging and discharging and therefore have poor cycling characteristics. Patent Literature 1 describes a non-aqueous electrolyte secondary battery that includes a silicon powder as a negative electrode active material and an elastic binder coating layer disposed on the surface of the silicon powder to reduce the influence of expansion and contraction of the negative electrode active material.